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No. 62l,876. Patented Mar. 28, 1899.

1 E. P. WARNER.

ELECTRIC ARC LAMP.

(Application filed Dec. 31, 1897.)

(No Model.)

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PATENT trio.

ERNEST P. VARNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE IVESTERN ELECTRIC COMPANY, OF SAME PLACE.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 621,876, dated March 28, 1899.

Application filed December 31, 1897. Serial No. 665,084. (NomodeL) To all whom, it may concern:

Be it known that I, ERNEST P. WARNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Electric-Arc Lamps, (Case No. 65,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification. I

My invention relates to electric-arc lamps; and its chief object is to provide means for securing substantially symmetrical burning or wearing away of the ends of the carbons.

It is well known that if an electric are be established within a magnetic field the arc will be distorted. This is equally true if a conductor carrying an electric current be brought near the arc, the magnetic whirls about the conductor producing a similar effect, and if a simple iron bar or other paramagnetic body be brought near the arc the magnetic effect of the arc itself by reason of the presence of the iron will cause a distortion. This phenomenon has caused considerable trouble in the burning of electric-arc lamps, in which the usual construction has been to I provide a single rod extending downward from .the main framework to support the lower carbon, this rod also serving to conduct current from the lower carbon upward to the negative terminal of the lamp. The current in the rod or the mere presence of the rod itself produces an appreciable effect upon the are, causing it to be deflected to one side of the carbons, so that the latter are consumed unsymmetrically. The unsymmetrical form of the tips of the carbons leaves projecting parts thereon, which, being near the light center, throw large shadows and partially exclude the light from that side of the lamp.

The principal feature of my invention consists, briefly, in providing a number of magnetic bodies, which, preferably, may be electric conductors, surrounding the arc and at such distances therefrom that the distorting eifect upon the arc of each of said magnetic bodies will be neutralized by the effects of the remaining magnetic bodies, so that the carbons are burned away evenly.

I have found that by dividing the current from the lower carbon into several parallel paths, so that the magnetic whirls set up by each portion will be in equal inductive relation to the arc, the latter will no longer be affected, (except that a slight rotary motion about its own axis may perhaps be imparted thereto,) and the carbons will consequently be so consumed that the faces of the tips will remain flat andin a plane at right angles with the length of the carbons. This result may be satisfactorily accomplished by providing three small rods, preferably of iron and of equal diameter, which support the lower carbon, and through each of which the current flows in approximately equal proportion from the lower carbon, said rods being at equal distances from the carbons and at equal distances from each other--that is, the angle between any two of the rods and the carbon being about one hundred and twenty degrees. Thus the magnetic whirls set up by the current in each rod have an equal effect upon the arc, and these effects being neutralized by each other the arc is free to travel around the ends of the carbons, wearing them away evenly.

An arc-lamp embodying my invention will be particularly described by reference to the accompanying drawings, in which- Figure 1 is a-diagrammatic View illustrating the ends of a pair of carbons which have been unsymmetrically consumed by the uneven on line 4 4 of Fig. 3.

Like letters of reference indicate like parts in all the figures.

By an inspection of Fig. 1 it will be seen that the magnetic whirls set up by the current flowing in the conductor a have caused the arc to be distorted to such a degree that the carbons a 1), instead of having flat ends the surfaces whereof are parallel, have been irregularly and unsymmetrically consumed, leaving projecting portions or b, which largely shut out the light from that side. In the arrangement shown in Fig. 2 the three conductors c c 0 carrying equal currents flowing in the same direction, are so disposed that their effects are mutually neutralized and the carbons burn with the faces of their tips fiat and parallel. Figs. 3 and 4 show substantially this same arrangement practically applied to an arc-lamp of otherwise well-known construction, except that my improved cutout is added thereto.

In the form of arc-lamp illustrated the upper carbon at is inclosed within the hollow core (1 of the solenoid d and is freely movablelongitudinallytherein. The clutching mechanism 6 is connected to said core andis adapted to grip and raise the carbon when the solenoid is energized in a manner well understood and needing no further description. A pin 6 projects from the clutching mechanism and the lever 6 pivoted at e to the frame of the lamp and connected with the dash-pot e rests upon the pin, this being the only connection which the clutching mechanism has with the dash-pot.

It will be perceived at a glance that upon upward movement of the clutching mechanism the pin e will engage the lever e and the motion of said clutching mechanism will be impeded by the retarding action of the dashpot. \Vhen, however, the clutching mechanism moves downward, the pin no longer will engage the lever e and the clutching mechanism may move free of the dash-pot. This construction is valuable when there are sudden fluctuations in the current for which the regulating mechanism would ordinarily move too slowly to compensate.

The lower carbon 1) is firmly clamped in the holder D which is supported by but thoroughly insulated from'the metallic rods 0 c 0 which are in turn supported by a post 0 mounted upon but insulated from the lampframe and electrically connected, preferably through resistance f, with the negative terminal N of the lamp. The only electrical connection which the lower carbon has with the rods 0 c c is by means of the cut-out couductor g, which is connected between the rod 0 and a post If, mounted upon the carbonholder 6 and which conductor preferably touches the carbon at the point 9'.

The current, entering at the binding post or terminal P, passes in series through the solenoid d and thence by way of the lampframe, flexible conductor 71, and clutching mechanism 6 to the upper carbon. Crossing by the arc to the lower carbon it flows through the cut-out conductor 9 to the three rods 0 0 0 where it divides, passing through the rods in parallel and thence by way of the post 0 and resistance f to the negative terminal N of the lamp. Since the effects of the magnetic whirls set up by the currents in the rods 0 c c are practically equal, they will neutralize each other and the are will thus be free to travel around the faces of the ends of the carbons, the latter being evenly worn away. The lamp will burn in this manner until the lower carbon is consumed down to the point where the cut-out conductor 9 touches it, when the arc will transfer itself to the conductor. The latter will be fused immediately and the circuit through the lamp thus broken. Even if the conductor g does not come in contact with the carbon 1) the heat of the arc will produce the same result. It will be observed that the supporting-rods, being of small diameter, will throw little, if any, shadow, while a single rod to be strong enough for the purpose of supporting the carbon willnecessarily be of such diameter as to seriously obstruct the light on that side of the lamp.

Obviously the number of side rods may be varied and other modifications made without departing from the spirit of my invention, and I do not wish to be understood as limiting the application of my invention to the precise form of arc-lamp illustrated in the drawings; but,

Having thus described my invention, what I claim as new, and desire to secure by these Letters Patent, is-

1. In an electric-arc lamp, the combination with a pair of carbons between which the arc is formed, of means for supplying electric current to said are, and a plurality of magnetic bodies surrounding the are at such distances therefrom that the distorting effect upon the arc of each magnetic body will be neutralized by the efiects of the remaining magnetic bodies, whereby substantially symmetrical burning away of the ends of the carbons is secured, substantially as set forth.

2. In an electric-arc lamp, the combination with a pair of carbons between the ends of which the arc is formed, of a plurality of conductors adapted to support one of the carbons, said conductors being arranged around the carbons at substantially equal distances therefrom and at substantially equal distances from each other, and means for directing an electric current through said rods in parallel, whereby the distorting effect upon the are of the current in each conductor is neutralized by the eifects of the currents in the remaining conductors, substantially as described.

3. In an electric-arc lamp, the combination with a pair of carbons between which the are is formed, of a plurality of electric conductors surrounding the arc, and means for directing an electric current through said conductors, whereby the distorting eifect upon the arc of each conductor is neutralized by the efiects of the currents in the remaining conductors, substantially as described.

4. In an electric-arc lamp, the combination with a pair of carbons between which the arc is formed, of means for supplying current to the movable carbon, a plurality of conduct ing-rods arranged about the carbons at substantially equal distances therefrom, and at substantially equal distances from each other, said rods being adapted to support the stationary carbon, and a fusible conductor in electrical connection with said stationary carbon and in actual or approximate contact therewith, said fusible conductor being electrically connected with said conducting-rods in parallel, substantially as and for the purposes described.

5. In an electric-arc lamp, the combination with a pair of carbons between which the arc is formed, of means for supplying current to the movable carbon, a plurality of conducting-rods arranged about the carbon at substantially equal distances therefrom and at substantially equal distances from each other, said rods being adapted to support the sta ERNEST P. WARNER.

Witnesses:

D. W. C. TANNER, GEORGE L. CRAGG. 

